EA has detailed the 'Premier Edition' package for Red Alert 3, which apart from the obligatory tin comes with an "Exclusive Beta Key to a future C&C game."
The only announced franchise entry on the horizon is FPS cross-over Tiberium, but that's not due out for a while yet - possibly too long to warrant a beta test this year.
The speculation has already kicked off then that this "future C&C game" could in fact be Command & Conquer 4, or perhaps a new entry in the Generals series.
Interestingly, both the standard and PE packs also include a "Red Alert 3-exclusive item" for Warhammer Online: Age of Reckoning. We're hoping it's some sort of mini tesla-coil.